Road Workers Safety Forum. Trials Team. Trial Report: On-Road Monitoring of Innovative Taper

Road Workers Safety Forum Trials Team Trial Report: M25 Motorway, 2007-2008

TABLE OF CONTENTS 1 INTRODUCTION...1 1.1 Description of Innovative Taper Technique... 2 1.2 History of Development and Evaluation of Innovative Taper... 3 2 TRIAL METHOD...5 2.1 Data collection for taper placement and retrieval.... 5 2.2 Traffic data analysis.... 7 2.3 User assessments... 7 3 RESULTS...10 3.1 On-road monitoring of the taper placement and retrieval... 10 3.2 Traffic data analysis... 11 3.3 Car driver perception assessment... 14 3.4 Heavy goods vehicle driver perception assessment... 20 3.5 Road worker benefits assessment... 23 4 CONCLUSIONS AND SUMMARY...27 Car and Truck Driver Questionnaire... 29 i

1 INTRODUCTION Road works are a necessary part of the maintenance of a modern road network and temporary lane closures are an essential tool that enables maintenance operations to be carried out safely. The Road Workers Safety Forum Trials Team exists to trial equipment and techniques that can improve the safety of road workers. This includes any measures that have the potential to reduce risk to personnel involved in the installation and removal of lane closures. The most hazardous activity in closing a live lane is establishing the initial angled line of cones that closes the lane, known as the cone taper. Although the introduction (championed by RoWSaF) of sequentially flashing road danger lamps on the cone taper has reduced taper collisions by a significant amount, there is still a significant element of risk to the road workers involved in setting out the taper. One potential method to improve the safety of road workers is to reduce the time spent in the carriageway installing and removing lane closures. An innovative cone taper layout that was designed to achieve this safety improvement was proposed to RoWSaF by Carillion plc. This method (referred to as the innovative taper in this report) was designed to reduce the number of cones required in a cone taper and thus reduce the time taken to install and/or remove a lane closure. This report presents the findings of a limited area roll-out of the innovative taper, which was conducted following successful off-road trials and an initial deployment of the technique on a live carriageway. It provides a description of the technique, its development and the effects of the innovative taper on road worker and road user safety. 1

1.1 Description of Innovative Taper Technique The established technique for setting out a lane closure taper (as specified in the Traffic Signs Manual Chapter 8: Traffic Safety Measures and Signs for Road Works and Temporary Situations Part 1: Design) requires a line of cones to be placed diagonally across the lane to be closed (referred to as the conventional taper ). The cones are spaced at 3 metre centres in the arrangement shown in Figure 1 below. The innovative method uses rows of cones placed perpendicular to the direction of traffic flow and spaced at 30m centres, with only two intermediate cones spaced equally (10 metre centres) between the perpendicular rows. This arrangement is shown in Figure 2 below: 246m 246m 150m 150m 120m 90m 60m 30m 0m 0m Figure 1: Conventional taper layout (Chapter 8 Plan DZB6 1 ) Figure 2: Innovative taper layout 1 Lane-change zone for a single lane closure on a dual carriageway road with a hard shoulder for which the national speed limit applies, Plan DZB6, Section D6.15, Traffic Signs Manual Chapter 8: Traffic Safety Measures and Signs for Road Works and Temporary Situations, Part 1: Design (2006), TSO London 2

The innovative taper requires only 31 cones to establish a single lane closure compared to the 51 cones required to establish a lane closure using a conventional taper. The reduced number of cones in the innovative taper is balanced by the arrangement of perpendicular rows which gives the appearance of a wall of cones and thus the illusion of solidity to the taper. A further benefit of the reduced number of cones required for the innovative taper is a reduced manual handling requirement, estimated by industry to be around 50% of that of deploying a conventional taper. 1.2 History of Development and Evaluation of Innovative Taper The innovative taper layout was originally suggested to the Road Workers Safety Forum (RoWSaF) by Carillion. The development and evaluation of the innovative taper by RoWSaF took place in three stages:- 1) An off-road trial at TRL s test track was carried out on 30 th November 2006 by the RoWSaF Trials Team. This trial took place to evaluate the concept and develop an optimum design for the innovative taper. Stakeholders from RoWSaF and the wider traffic management industry were present to provide their feedback and assist with development suggestions. The outcome of the trial was the design shown in Figure 2 above. The positive reception from RoWSaF encouraged Carillion and the Highways Agency to propose an initial deployment of the innovative taper on a section of the network in Area 8 with low traffic flow. 2) A pilot deployment on a live carriageway took place on the M45 motorway on 17 th May 2007 under the control of CarillionWSP. Members of RoWSaF and key stakeholders from the traffic management industry were again present as observers. Comparison measurements were taken of traffic behaviour when approaching an innovative and conventional taper and video and still photographs were taken of the trial. A detailed chronology was also made of deployment and removal of each taper type to establish the potential level of time savings from the new technique. The monitoring of the trial was documented in a Trials Team report presented to the RoWSaF Working Group. 2 2 Road Worker Safety Forum Trials Team Trial Report: On-Road Evaluation of Innovative Taper M45 motorway, 17th May 2007 (2007), Report version 2.01, dated June 2007,TRL Limited, Wokingham 3

3) The initial deployment of the innovative taper on the M45 was considered sufficiently successful to warrant a limited area roll-out in Area 5, again under the control of Carillion. Approval was sought from the Agency to undertake multiple deployments of the innovative taper in live traffic conditions over a period of several months. These trials were monitored on site and from traffic data, with user perceptions of the new taper measured in a parallel exercise. This report summarises the findings from the monitoring of the limited area roll-out and supporting work carried out by the Trials Team. 4

2 TRIAL METHOD Monitoring and evaluation of the limited area roll-out of the innovative taper took place over a number of months (late 2007-2008). The programme of work comprised five main parts: 2.1 Data collection for taper placement and retrieval. Three sources of data were collected for the trial. 2.1.1 Video and photographic data Video data of sample night-time deployment of the innovative taper were collected from a suitable vantage point (a bridge adjacent to the taper). The main site-based monitoring was carried out between Junction 9 and 10 of the M25 in March 2008. Figures 1 and 2 - Views of innovative taper from an overbridge, M25. Members of the Trials Team observed the setting-out process of the innovative taper that was being used to establish the Lane 1 closure. The setting-out process was recorded both by video and stills photography. Once the lane closure was established, car driver s eye height video data was recorded of the innovative taper and a conventional taper set out on the opposite carriageway. Two sets of video data were collected for each taper. The first of these involved the taper in Lane 1 being approached in Lane 1 with a lane change manoeuvre from Lane 1 to Lane 2 carried out adjacent to the taper. A second set of video data was collected by approaching the taper in Lane 2 with no lane change manoeuvre taking place. 5

Further video data were collected for both types of taper as it was known from previous Trials Team work on road works signing that visual perception is dependent on viewing angle. With the assistance of Carillion, video data were collected for both innovative and conventional tapers from a heavy goods (traffic management) vehicle. This gave a driver s eye viewing height of approximately 2.9m, compared to approximately 1.1m for the video data collected from the car driver s eye height. 2.1.2 Traffic flow data As part of the limited area roll-out, the Area 5 team at Carillion were requested to provide the Trials Team with locations and dates of road works activity where innovative tapers were used. Similar data were also requested for conventional tapers for the purposes of comparison. This information was then used to acquire traffic flow data for road works using both types of taper. As part of the roll-out, Carillion were also requested to collect any details of taper strikes for both conventional and innovative tapers. These two sources of data were required to provide an indication of how many vehicles had passed the innovative taper, how many collisions had occurred and hence assess the safety of the innovative taper relative to a conventional cone taper arrangement. 2.1.3 Deployment and removal time data The Area 5 team were also asked to record the time taken to deploy and retrieve the innovative taper. This was required to give a clearer indication of the time savings that could be achieved through the application of the technique, as the earlier offroad and on-road trials had demonstrated some variability in timings. The earlier variability was thought to result from the lack of experience of the traffic management personnel involved in deploying and removing the innovative tapers under trial conditions. It was anticipated that wider use of the technique and thus personnel gaining experience in its use would give a more robust indication of potential time savings and the consequent reduction in risk from exposure to live traffic. 6

2.2 Traffic data analysis. An essential part of the limited area roll-out was assessing any potential change in risk to road users arising from the use of the innovative taper. The level of exposure to traffic for innovative and conventional tapers was calculated based on the average number of vehicles passing each type of taper during the limited area roll-out. This ensured that the conventional and innovative tapers were used on roads with similar levels of traffic flow. The only measure of collision risk that could be obtained from the limited area roll-out was to examine the number of collisions with each taper type and compensate for exposure to traffic. Industry reports suggest that the number of collisions with tapers has dropped significantly as a consequence of the use of sequentially flashing road danger lamps (SFRDLs) on the taper. This made it unlikely that a collision with the taper would occur as SFRDLs were used on each innovative taper deployed. It was therefore assumed that if the results of the comparison of collision rates showed that the rates were equivalent then the collision risk to road users from the use of the innovative taper could be considered to be no greater than for the use of a conventional taper. 2.3 User assessments User assessments were carried out to provide data on the public and workforce perceptions of the innovative taper. 2.3.1 Car driver perception assessment. Video data of the innovative and conventional tapers taken from the car driver s eye height were processed to produce a series of video excerpts. These were normalised as far as possible to ensure that each started 200m away from the taper, continued through to the end of works and was around 35 seconds in length. 7

Eight excerpts were prepared, which were divided into two sets; one for daylight (taken from the M45 pilot deployment video data) and one for night-time (from the M25 limited area roll-out video data) as shown in Table 1. Excerpt set Lighting conditions & video data source Taper type Approach lane Excerpt designation Daylight (M45) Conventional 1 DC1 1 Daylight (M45) Innovative 1 DI1 Daylight (M45) Conventional 2 DC2 Daylight (M45) Innovative 2 DI2 Night-time (M25) Conventional 1 NC1 2 Night time (M25) Innovative 1 NI1 Night time (M25) Conventional 2 NC2 Night time (M25) Innovative 2 NI2 Table 1: Arrangement of car driver perception assessment video excerpts Each set contains two pairs of excerpts. Each pair of excerpts compared conventional and innovative tapers viewed from the same lane. To offset any potential bias in the results, the presentation order was randomised. Each participant was shown one of the two sets (four excerpts in total). Instructions to the participants were carefully worded to avoid alerting the participants to look for differences in the traffic management (see Appendix for the participant questionnaire). The participant was shown the first two excerpts from the set and asked a number of questions. They were then shown the remaining excerpts and asked further questions. Participants were members of the public who held current driving licences and drove on a regular basis. Whilst efforts were made to ensure a broad demographic, there was nevertheless a weighting towards females under 30. All participants held a full driving licence for Category B vehicles (car / light van) and were regular drivers. 8

2.3.2 Heavy Goods Vehicle driver perception assessment. A similar methodology was used for the heavy goods vehicle (HGV) driver perception assessment as for the car driver perception assessment. The night-time video data collected from the HGV driver s eye view was processed to produce a series of video excerpts similar to those described in Section 2.3.1. HGV driver perception was measured using the same questionnaire structure employed for the car driver perception assessment, with the key difference being that the number of sets of excerpts was halved as only night-time assessments were carried out with the HGV drivers. Members of the Trials Team surveyed 16 HGV drivers at the M25 South Mimms motorway service area. The age range of drivers was wider than for the car drivers and the sample was biased towards males. 2.3.3 Road worker benefits assessment This assessment was carried out to examine the level of acceptance of the innovative taper technique amongst operatives experienced in its use. The assessment was also intended to identify any operational issues that could arise from the use of the innovative taper. A group of 37 traffic management operatives who had been using the innovative taper technique during the limited area roll-out were invited to participate in a survey. This survey was carried out on behalf of the Trials Team by a traffic management contractor working with Carillion and the results provided to the Trials Team for analysis and reporting. 9

3 Results 3.1 On-road monitoring of the taper placement and retrieval Observations of the deployment of an innovative taper made during the collection of video and still photography data showed that the taper took around ten minutes to install on a live lane closure when deployed from a traffic management installation vehicle. Further deployment and removal time data were collected for the Trials Team. This data was obtained by Carillion from Associated Asphalt Traffic Management, one of Carillion s sub-contractors. It was reported that across the installation of 520 innovative tapers, the average time taken to install the taper was between six and seven minutes, with the average time taken for taper removal of six minutes. Further time data were obtained directly from Carillion Traffic Management, which stated: Carillion Traffic Management has been trailing [sic] the new taper system on Area 5... using four T[raffic] M[anagement] Gangs, Monday to Friday. In this time we have installed over 150 closures using the new taper... The feed back [from the operatives] indicates that is that it is now taking them less time than when they first started. Time is now down to 10 minutes when dropped from the Traffic Management Installation Vehicle and 5 minutes if it is just being walked on from the side of the road. 3 This time data suggests that the average time taken to deploy or remove an innovative taper is 6-10 minutes. For comparison, the time reported by the traffic management industry for an experienced traffic management crew to place or remove a conventional taper is 15-20 minutes. The data suggest that a 50-70% reduction in time to deploy a single lane closure taper was achieved by using the innovative layout. This has the potential to significantly reduce road worker exposure to risk by reducing the time taken to set out and remove temporary traffic management. 3 Carillion Traffic Management Memo A109.CH.MEMO.081 from Chris Heyball to Andy Hicks, dated 2 nd October 2008 10

3.2 Traffic data analysis An indication of exposure of the innovative taper to traffic in the trial area was calculated by obtaining traffic count data (from the HA s MIDAS network and from the NTCC) for 34 innovative taper deployments and 10 conventional taper deployments. For the deployments examined, the traffic data indicated that a total of 71,464 vehicles had passed by innovative taper works during the two sampling periods. This gave an average (mean) of 2,102 vehicles passing each innovative taper. The traffic counts at the sites where conventional tapers had been deployed totalled 29,193 vehicles, giving an average (mean) of 2,919 vehicles passing each conventional taper. The difference between the two average traffic counts is a consequence of the much larger range in the innovative tapers (between 178 4,376 vehicles) compared to the smaller sample of conventional tapers (1,749 4,183 vehicles). However, the counts were of similar magnitude and thus traffic levels past each type of taper were considered comparable. Data from the two sampling periods are presented in Table 2 (conventional taper deployments) and Table 3 (innovative taper deployments): Date Road Junctions Carriageway Count Source 05/06/2008 M25 J10-11 B 3710 MIDAS 09/06/2008 M25 J5-6 A 2609 MIDAS 10/06/2008 M25 J4 B 1749 MIDAS 10/06/2008 M25 J3-4 A 2029 MIDAS 12/06/2008 M25 J8-9 A 3474 MIDAS 16/06/2008 M25 J9 B 2881 MIDAS 17/06/2008 M25 J8-9 A 3288 MIDAS 20/06/2008 M25 J8-9 B 4183 MIDAS 24/06/2008 M25 J9-10 B 1787 MIDAS 25/06/2008 M25 J8-9 B 3483 MIDAS Total Flow 29193 Table 2 - Flow Data for Conventional Taper Deployments 11

Date Road Junctions Carriageway Count Source 02/01/2008 A20 Swanley to Sidcup 688 NTCC 02/01/2008 A20 Swanley to Sidcup 843 NTCC 03/01/2008 M25 4-5 B 1550 MIDAS 03/01/2008 A3 Esher to Painshill 817 NTCC 03/01/2008 A3 Esher to Painshill 761 NTCC 03/01/2008 M25 7-8 B 2222 MIDAS 10/01/2008 M25 6-7 A 2108 MIDAS 18/01/2008 M25 7 B 1749 MIDAS 23/01/2008 M25 3-4 A 1433 MIDAS 23/01/2008 M25 3-4 B 1504 MIDAS 23/01/2008 M3 1-2 A 916 NTCC 24/01/2008 M23 Hooley to M25 A 736 NTCC 25/01/2008 M23 8-9 A 2908 MIDAS 25/01/2008 M23 8-9 B 2881 MIDAS 25/01/2008 M25 7-8 B 3357 MIDAS 31/01/2008 M25 5-6 B 196 NTCC 07/02/2008 M25 5-6 A 245 NTCC 04/06/2008 M25 J4-5 N 1964 MIDAS 05/06/2008 M25 J10-11 A 3374 MIDAS 05/06/2008 M25 J10-11 B 3710 MIDAS 05/06/2008 M25 J10-11 B 3307 MIDAS 09/06/2008 M25 J11 M 178 MIDAS 11/06/2008 M25 J8-9 B 3721 MIDAS 12/06/2008 M25 J4 M 297 MIDAS 12/06/2008 M25 J8-9 B 3365 MIDAS 12/06/2008 M25 J7-8 B 3529 MIDAS 13/06/2008 M25 J3-4 A 2528 MIDAS 13/06/2008 M25 J3-4 B 2599 MIDAS 16/06/2008 M23 J8-9 A 3387 MIDAS 17/06/2008 M25 J4-5 B 1998 MIDAS 18/06/2008 M25 J3-4 A 2007 MIDAS 18/06/2008 M25 J3-4 B 2001 MIDAS 20/06/2008 M23 J8-9 A 4209 MIDAS 20/06/2008 M23 J8-9 B 4376 MIDAS Total Flow 71464 Table 3 - Flow Data for Innovative Taper Road Works During the limited area roll-out, none of the tapers (conventional or innovative) were struck by any vehicle driven by a member of the public. The lack of taper strikes during the monitoring period supported the industry view that taper strikes have reduced substantially since the introduction of sequentially flashing road danger lamps (SFRDLs) on cone tapers. Continued monitoring carried out by Carillion plc indicated that no instances of a road user colliding with an innovative taper occurred after the sampling period. 12

The absence of any collision with either type of taper made it impossible to calculate a collision rate per vehicle for either innovative or conventional taper. However, the absence of any collisions with the innovative taper suggested that the collision risk to road users from the use of the innovative taper cannot be any greater than for the use of a conventional taper. This in turn implied that the innovative taper layout carried no greater risk of a road user colliding with it than the conventional Chapter 8 taper layout. Towards the end of the limited area roll-out, there was an incident where a heavy goods vehicle struck a traffic management vehicle. The traffic management vehicle was parked stationary on the hard shoulder. The traffic management operatives were in the final stages of clearing away a relaxed layout closure of Lanes 3 and 2 and as part of this work they were removing the 200 yards lane closure advance warning sign. Whilst there had been an innovative taper downstream of the advance warning sign location, this had already been completely removed some time before the collision occurred. There is no evidence to indicate that the innovative taper was either a causative or contributory factor in this collision. 13

3.3 Car driver perception assessment The car driver perception assessment was carried out on 46 drivers. The age and sex distribution of the sample of drivers is shown in Figures 5 and 6 below: 30 25 Number of Participants 20 15 10 Night Day 5 0 Under 30 30-45 45-60 Age Group Figure 5 - Participant age (car driver perception assessment) 25 20 Number of Participants 15 10 Night Day 5 0 Female Gender Male Figure 6 - Participant gender (car driver perception assessment) The results of the car driver perception assessment were examined by time of day, with an overall analysis of the clarity of taper types. 14

3.3.1 Daytime perception assessment The twenty-four participants who undertook the daytime perception assessment were asked after viewing the first two video excerpts what differences (if any) they had noticed. Twenty-one of the participants said that they noticed differences, whereas three said they did not. The participants who had indicated they had noticed differences were then asked to expand on the differences they had observed and to comment on the relative clarity of the two taper arrangements. The participants were then shown the second two video excerpts and asked the same questions. There is no evidence of a learning effect in the data from the second assessment as eighteen participants (14% fewer) said that they noticed differences compared to six who said there were none. Participants who had noticed differences were again asked to expand on the differences they had observed. For the daytime excerpts, the distribution of differences noticed by the participants is shown in Figure 7: 11% 5% 14% 8% 3% 11% 9% 17% 3% Vehicles Road Maintenance vehicles Signs Road markings Distance to closure Cones Not sure None personnel 19% Figure 7 - Differences noticed by car drivers (daytime excerpts) 8% of participants mentioned cones when commenting on differences between the excerpts viewed. None of these participants explicitly identified a difference between the layouts of the tapers. Most participants commented on the proximity of the cones to an overbridge present in the video, with others commenting that the cones downstream of the innovative taper were further away from the live lane than in the 15

conventional taper video excerpt. One participant stated that they had observed cones in one excerpt but not in the other, even though they were clearly visible in both excerpts. The greatest number of participants noticed differences in the road markings. This occurred as a result of the location of the innovative taper during the M45 pilot deployment, which was 500m upstream of a roundabout which featured transverse yellow bar markings on the approach. These were not present in the video excerpt for the conventional taper as this had been placed on the opposite side of the carriageway. Comments were also made regarding the signing. Although the temporary road works signing was consistent between the excerpts, there were differences between the permanent signing visible in each excerpt. Comments on vehicles were a result of the differences in other traffic between the two excerpts. Several participants remarked that the innovative taper was further away from the start of the excerpt than for the conventional taper, even though the excerpts had been carefully prepared to ensure they started at equivalent locations immediately after the 400 yard advance warning sign. Once the participants had expanded on the differences they noticed, where appropriate, they were asked which of the videos they thought presented a clearer message of what they, as a driver, had to do. The results are shown in Figure 8. 25 20 Number of participants 15 10 5 0 Innovative Conventional Both the Same Neither Taper Clarity Figure 8 Car drivers rating of taper clarity (daytime excerpts) 16

For the daytime perception there was a statistically significant difference in the choice of taper clarity expressed, with a majority of drivers considering that the innovative taper was clearer (t= 6.05 p<1%). 3.3.2 Night-time perception assessment For the night-time perception assessment, eighteen of the twenty-two participants noted differences between the first pair of video excerpts and four who did not. There was a small difference for the second pair of excerpts, with 20 participants noting differences compared to two who did not. For the night-time perception assessment, the distribution of differences identified by the participants was as shown in Figure 9: 10% 2% 12% 25% 5% 2% 32% 8% 2% Vehicles Road Maintenance vehicles Signs Road markings Distance to closure Cones Not sure None personnel 2% Figure 9 - Differences noticed by car drivers (night-time perception assessment) Signing was the most frequently noticed difference. This was most probably due to the presence of a permanent variable message sign (VMS) adjacent to the innovative taper and the absence of any equivalent VMS in the conventional taper video excerpt. (The VMS adjacent to the innovative taper was not displaying any information at the time the video data were collected.) 17

Many respondents observed that there was a greater distance to the road closure in the case of the innovative taper, even though the video excerpts had been carefully prepared to ensure the approaches to each type of taper were equivalent. The comments from participants could have been a consequence of the locations of the tapers, as the innovative taper was placed on a section of carriageway with a slight left-handed curve and the conventional taper was placed on the opposite side and thus was on a slight right-handed curve. However, as the comments regarding a perceived greater distance to the innovative taper were consistent with the daytime perception assessment, these results may indicate a real effect. The innovative taper may possibly have given an earlier warning of the lane closure to the assessment participants, thus apparently expanding the perceived distance to the taper. This effect would require further investigation but may represent an additional yet unanticipated benefit of using the innovative taper. The differences identified by those participants who viewed the night-time video excerpts were mainly unrelated to the arrangement of cones in the two tapers. Although cones were mentioned in 5% of post-viewing responses, none of the participants explicitly stated that they had noticed a difference in the cone layouts. In the night time analysis there was a shift towards finding the conventional taper clearer. This can be seen in Figure 10 below: 20 18 16 Number of Participants 14 12 10 8 6 4 2 0 Innovative Conventional Both the Same Neither Taper Clarity Figure 10 Car drivers rating of taper clarity (night-time excerpts) 18

The rated difference in clarity between the innovative and conventional tapers was statistically significant (t=4.53, p<1%). The reason for the major difference in clarity rating in the night-time data (Figure 10) compared to the daytime data (Figure 8) was not fully identified. Factors that may have had an influence were differences in the road layout (2-lane vs. 4-lane) or comparison of an outside lane closure in the day with a nearside lane closure at night, which were defined by operational parameters outside of the control of the Trials Team. It is likely that the greatest influences on participant perception were the variations in quality between the daytime and night-time video data. Under low light conditions video data is not particularly effective at reproducing lit or reflective materials such as lamps, cones and signs. Additionally, the colour balance of the night-time video data was also considerably affected by the low-pressure sodium vapour lights on the motorway. This type of lighting changes the apparent colour of objects due to the very specific wavelength (589nm) of the sodium vapour lamp. This effect is particularly an issue for red or red/orange objects such as the cones in the tapers and thus may have influenced participants views. 3.3.3 Overall clarity of conventional and innovative tapers The results from participants rating of the taper types in terms of the clarity were aggregated and are presented in Figure 11 below. 35 30 Number of Participants 25 20 15 10 5 0 Innovative Conventional Both the Same Neither Taper Clarity Figure 11 Clarity of taper arrangement (all car drivers) 19

The majority of participants rated innovative tapers and conventional tapers of comparable clarity. There is no statistically significant difference between the number of participants finding the innovative taper clearer than the conventional taper (t=1.07, p=29.0%). There is also no statistically significant difference between the numbers of participants finding the tapers both the same and those preferring the innovative (t=0.76 p=45.3%) or conventional taper (t=1.82 p=7.4%). The lack of significance in the aggregated data indicates that there was no significant difference in clarity between innovative and conventional tapers. 3.4 Heavy goods vehicle driver perception assessment The distribution of heavy goods vehicle (HGV) drivers who participated in the perception assessment was significantly different to the participants in the car driver sample. The HGV driver sample was smaller, more heavily biased to male drivers and towards the upper end of the age range. The distributions of age and sex of participants are shown in Figures 12 and 13: 10 8 Number of Participants 6 4 2 0 30-45 45-60 60+ Age Group Figure 12 - Participant age (HGV driver perception assessment) 20

14 12 Number of Participants 10 8 6 4 2 0 Female Gender Male Figure 13 - Participant gender (truck survey) The HGV driver perception assessment used night-time excerpts from video data collected from an HGV driver s eye height. Participants were asked to respond to the same questionnaire structure used for the car driver perception assessment and describe any observed differences between two sets of two video excerpts None of the HGV drivers who participated in the assessment specifically identified that there was a different layout of cones. An inactive variable message sign (VMS) that was present in one video excerpt but not the other was noted, together with other differences ranging from the topography of the roads to the presence of other vehicles. However there were no consistent differences reported by the participants. One driver stated that he had observed a gap in the cones in the innovative taper excerpt. This referred to the works access downstream of the taper, which was not part of the assessment as it did not relate to the taper itself. The presence of a flashing lamp at the works access may have drawn his attention to this location as there was a static (non-flashing) lamp marking the works access on the conventional taper. Overall, most participants considered the clarity of the two taper arrangements to be similar as shown in Figure 14 below: 21

22 20 18 16 Number of Participants 14 12 10 8 6 4 2 0 Innovative Conventional Both the Same Taper Clarity Figure 14 - Clarity of taper arrangement (HGV driver perception assessment) For HGV drivers who expressed an opinion regarding the clarity of the tapers, a small proportion considered the conventional taper to be clearer. However, the majority (65%) of participants viewed the two tapers as of similar clarity. This suggested that HGV drivers did not view the innovative taper as significantly different to a conventional taper. 22

3.5 Road worker benefits assessment The review of the road worker benefits assessment carried out for the Trials Team by the traffic management contractor highlighted the following issues: In response to the first question Do you feel comfortable with the new taper?, 28 operatives said that they were comfortable with the new taper and eight indicated they were not. Positive remarks obtained from those who felt comfortable centred on the ease and speed of deployment and removal of the new taper and associated benefits to the road worker. Negative comments were largely based around the dislike of change and the requirement to learn a new technique. Answers to the second question Is there any part of the setting out of the taper that you feel could be improved? were consistent with the Question 1 responses. All respondents except two stated that the current innovative taper deployment method was good. One of the positive comments suggested that the spacing of the intermediate cones should be revised to 9m instead of 10m to make them consistent with the spacing of the road markings. The two respondents who indicated improvements could be made both proposed using the conventional taper method instead of the innovative taper but did not provide any information as to why they considered it better than the innovative layout. This appeared to be an echo of the points made in response to Question 1 by those operatives who did not like the innovative taper arrangement. Answers to question 3 Is there any part of the picking up of the taper that you feel could be improved? indicated that the taper removal process was viewed as acceptable, with the majority of respondents indicating that they were happy with the current procedure. Two respondents specifically mentioned that care must be taken during the removal of the innovative taper as the traffic management vehicle is required to reverse in close proximity to road workers on the carriageway. 23

Road worker responses to question 4 Has the time spent installing the taper decreased or increased? varied as shown in Figure 15 Question 4 - Has the time spent installing the taper decreased or increased? Increase Decrease Same Other Figure 15 Change in time taken to install taper (road worker assessment) Twenty-four respondents said that they felt that the innovative taper was quicker to put out and retrieve than the conventional one, with four saying that it took the same time and one saying that it increased installation time. From those road workers who had experienced a reduction in time taken, a figure of five minutes per procedure was mentioned. The respondent who said that the installation time had increased did not provide any estimate of the additional time taken, why they were of this opinion or provide any additional useful information. The remaining respondents (classed as other ) did not express any opinion. The purpose of question 5 How does the taper look to you once installed? was to obtain the opinions of operatives as to whether the visual appearance of the innovative taper layout was as good as that of a conventional taper. Comments received were mainly positive, though some respondents voiced concerns that the spacing between cones was too large and might enable vehicles to pass through. 24

Responses to question 6 Is the taper easier or harder to install than the conventional taper? indicated that most operatives viewed the innovative taper as easier to install compared to the conventional layout, as shown in Figure 16: Question 6 - Is the taper easier or harder to install than the conventional taper? Easier Harder Same Other Figure 16 Ease of installation of innovative taper (road worker assessment) Twenty-three respondents said that they found that the innovative taper was easier to install than the conventional, compared to four who said it was harder and five who said that it was comparable to the conventional method. Two respondents specifically commented that the innovative taper technique was easier for inexperienced TM operatives to learn than the conventional taper technique. The remaining respondents (classed as other ) did not express any opinion. The safety performance of the innovative taper was addressed in Question 7 Is there a difference between nearside and offside layouts in respect to health and safety? Twenty-one participants claimed there were no operational differences between deployment of innovative tapers on the nearside and offside of the carriageway. Six responses claimed that it did make a difference, though the differences were not specified and the same number of respondents claimed there was a difference for nearside deployments as claimed there was a difference for offside deployments. The final question Would you like to continue with the trial? was included to gain an indication of industry s likely acceptance of the technique. The majority of TM 25

operatives polled said that they would like to continue with the on-road trial of the innovative taper. The road worker benefits assessment suggested that a majority of operatives were in favour of the innovative taper technique and considered it provided a benefit to road workers. A number of specific points were noted from the assessment that should be considered as part of any further roll-out of the taper technique: Operatives commented that when laying the innovative taper the traffic management vehicle had to start and stop frequently during installation and removal. This made it more difficult for the operative working on the back of the truck to remain standing. Two comments were that the visual effect of the taper was best suited to single lane drops of lane 1 or the outside lane. One comment was received that it was easier for inexperienced TM operatives to gain proficiency in setting out the innovative taper. Operatives indicated that they liked the closer proximity of the TM vehicle to their location on the carriageway during placement and pickup. 26

4 CONCLUSIONS AND SUMMARY Monitoring of the limited area roll-out of the innovative taper was intended to establish whether the innovative taper could provide a safety benefit to road workers and to ensure the risk to road users was no greater than the equivalent conventional taper. The limited area roll-out was carried out in Area 5 and the key findings from the monitoring carried out by the Trials Team were: The time taken to install or remove an innovative taper was 50-70% of the time taken to install or remove a conventional taper Time savings (and thus reduction in exposure to live traffic) during the limited area roll-out were around 20 minutes per taper installation and removal The reduction in manual handling from using the innovative taper was around 50% when compared to a conventional taper Examination of the traffic count and accident data suggests that the collision risk to road users from the use of the innovative taper is not any greater than for the use of a conventional taper. This is in agreement with the user perception assessment for both car and HGV drivers, which showed users did not notice any major difference between the two taper layouts and there was no strong preference for either type of taper. The majority of road workers who had used the innovative taper felt it was easier to learn as well as quicker to install and remove compared to a conventional taper and consequently wished to continue with the trial. Although the results of this trial are consistent and suggest the innovative taper layout is safe for both road workers and road users, it is strongly recommended that the Agency should collect a substantial body of evidence to assess the long-term safety of the technique. 27

The Trials Team therefore recommends that wider use of the innovative taper is supported by monitoring of the technique. This would enable the Highways Agency to ensure any collisions with innovative tapers can be investigated and an assessment made of collision frequency and risk together with the effect on both the cone layout and the impacting vehicle. 28

APPENDIX Car and Truck Driver Questionnaire 29

Survey Questionnaire The Transport Research Laboratory is undertaking work on behalf of the Highways Agency to explore the effectiveness of road works equipment. We would like to show you four short videos and ask you a few questions which should take around 15 minutes. 1) Watch first two videos (clip 1 and clip 2). Did you notice any differences between what you saw in the two videos? Yes No 2) If yes, what were the differences that you noticed? 3) Did you feel that either video presented a clearer message of what you, as a driver, were supposed to do? Clip 1 was clearer Clip 2 was clearer I thought they were about the same I didn t understand either one 30

4) Watch second two videos (clip 3 and clip 4) Did you notice any differences between what you saw in the two videos? Yes No 5) If yes, what were the differences that you noticed? 6) Did you feel that either video presented a clearer message of what you, as a driver, were supposed to do? Clip 3 was clearer Clip 4 was clearer I thought they were about the same I didn t understand either one Finally, what sort of vehicles do you drive on the motorway? Car Van Commercial lorry/bus Other - e.g. motorcyclist - To be completed by interviewer - Participant Gender Male Female Age : Under 30 30-45 45-60 Over 60 Presentation B C D E 31